Development, validation, and applicability of a symptoms questionnaire for lactose malabsorption screening

Lactose intolerance awareness among adults in Riyadh, Saudi Arabia

Introduction

Lactose intolerance is a common medical condition characterized by malabsorption of lactose. Despite the considerable impact of lactose intolerance on affected persons, studies on its awareness are limited. The aim of study was to assess the awareness of lactose intolerance and its associated factors among the general population of Riyadh City, Saudi Arabia. The prevalence of lactose intolerance in the study population was also assessed.

Methods

This was a cross-sectional study conducted in Saudi Arabia. An online questionnaire, which included 15 questions on lactose intolerance awareness and the risk factors for lactose intolerance, was administered. The prevalence of lactose intolerance was assessed using a validated five-question screening tool. The student's t-test and analysis of variance were used to compare quantitative variables, whereas the chi-square test was used to determine the association between qualitative variables.

Results

A total of 2150 adult participants were included. The mean percentage of correct answers to questions regarding lactose intolerance awareness was 28.9 % (±21.9). Participants with a previous lactose intolerance diagnosis had the highest lactose intolerance knowledge scores (46.9 [±18.3]). Regarding the prevalence of lactose intolerance, 14.7 % of the participants responded that they were likely lactose intolerant, whereas 7.3 % reported that they were diagnosed with lactose intolerance by a physician. Results of the assessment performed using the screening tool, which had a sensitivity of 47 % in this study, showed that women were more likely to have lactose intolerance than men. In addition, women and younger participants had greater knowledge of lactose intolerance than men and older participants.

Conclusion

The Saudi Arabian population has a low awareness of lactose intolerance. The findings of this study provide valuable information regarding level of lactose intolerance awareness among the Saudi population and can be used for the development of effective programs for increasing lactose intolerance awareness in Saudi Arabia.

The impact of lactose intolerance diagnosis: costs, timing, and quality-of-life

Lactose intolerance (LI) is a very common condition but, despite many efforts of the Italian National Health Service to reduce diagnostic delay of chronic disorders and provide prompt treatments, its early diagnosis remains an unmet need. In addition, the COVID-19 pandemic has exacerbated this problem, due to the conversion of many public health services to COVID centers. This study aims to analyze the diagnostic journey of patients suffering from LI, taking into account the duration of the process, associated costs, and impact on quality of life. Anonymous surveys were designed and distributed to patients with LI as well as physicians involved in LI management. The data were analyzed to determine the time required for a reliable LI diagnosis and average costs. Diagnostic delay of LI proved to be longer than 2 years, its impact on quality of life proved to be moderate to high in most of participants, especially in their psychosocial domain, and average costs proved to be high. Further investigations are needed to determine the economic burden of maintaining an asymptomatic status in patients with LI.

Detection capacity of small intestine bacterial or methanogen overgrowth by lactose and fructose breath testing in the adult population

Objectives

Exhaled breath tests (BTs) are the main diagnostic method for fructose and lactose malabsorption/intolerance (FI and LI, respectively) and for detecting small intestine bacterial or methanogen overgrowth (SIBO/IMO). Although FI/LI-BTs may provide evidence of the presence of SIBO/IMO, there is limited literature evaluating their reliability for this purpose. The objective of this study was to assess the sensitivity and specificity of FI/LI-BTs in detecting SIBO and their concordance with SIBO-BTs in the identification of IMO.

Methods

In this retrospective observational study, FI/LI-BTs and SIBO-BTs performed in the same patients within a period of 6 weeks were selected from 652 gas chromatography-based BTs.

Results

A total of 146 BTs from 67 eligible adult patients were identified. LI-BTs had higher specificity than FI-BT in detecting SIBO (93.8 % vs. 72.7 %). In contrast, FI-BTs showed higher sensitivity (60.0 % vs. 28.6 %) as FI was more frequently established in SIBO-positive patients (70 % vs. 29 %). With regard to IMO, concordance with LI-BT was 100 %, with a 27 % of false negatives on FI-BTs.

Conclusions

Findings suggestive of SIBO or IMO on LI-BTs were highly consistent with those of SIBO-BTs. In contrast, the rate of false positives for SIBO and the rate of false negative for IMO on FI-BTs was 27 % in both cases.

Capacidad de detección de sobrecrecimiento bacteriano o metanogénico intestinal de los test de aliento para intolerancia a lactosa y fructosa en población adulta

Objetivos

Los test de aliento espirado (TAE) son la principal herramienta diagnóstica en la evaluación de la malabsorción/intolerancia a fructosa (IF) y lactosa (IL) y para la detección del sobrecrecimiento bacteriano o metanógenico intestinal (SCBI/SCMI). En ocasiones, los TAE-IF/IL muestran hallazgos sugerentes de la presencia de SCBI o SCMI, pero los estudios que evalúan la fiabilidad de éstos son escasos. Nuestro objetivo es analizar la sensibilidad y especificidad de los TAE-IF/IL en la detección de SCBI y la concordancia en la identificación de SCMI.

Métodos

Estudio observacional retrospectivo donde se seleccionaron entre 652 TAE realizados mediante cromatografía de gases aquellos TAE-IF/IL y TAE-SCBI hechos en un mismo paciente en un plazo máximo de 6 semanas.

Resultados

Se encontraron 146 TAE de 67 pacientes adultos que cumplieron el criterio de selección. La especificidad para la detección de SCBI fue mejor para el TAE-IL que para TAE-IF (93,8 vs. 72,7 %). La sensibilidad fue más alta para el TAE-IF (60,0 vs. 28,6 %), porque se observó un mayor porcentaje de IF que de IL entre los pacientes con SCBI positivo (70 vs. 29 %). Para SCMI, la concordancia fue del 100 % para TAE-IL y hubo un 27 % de falsos negativos en TAE-IF.

Conclusiones

Los hallazgos de SCBI o SCMI encontrados en el TAE-IL son altamente concordantes con los obtenidos en la prueba TAE-SCBI, mientras que los TAE-IF presentan en torno a un 27 % de falsos positivos en la detección de SCBI y otro 27 % de falsos negativos en la identificación de SCMI.

The impact of heat treatment of bovine milk on gastric emptying and nutrient appearance in peripheral circulation in healthy females: a randomized controlled trial comparing pasteurized and ultra-high temperature milk

BACKGROUND

Heat treatments of dairy, including pasteurization and ultra-high temperature (UHT) processing, alter milk macromolecular structures, and ultimately affect digestion. In vitro, animal, and human studies show faster nutrient release or circulating appearance after consuming UHT milk (UHT-M) compared with pasteurized milk (PAST-M), with a faster gastric emptying (GE) rate proposed as a possible mechanism.

OBJECTIVES

To investigate the impact of milk heat treatment on GE as a mechanism of faster nutrient appearance in blood. We hypothesized that GE and circulating nutrient delivery following consumption would be faster for UHT-M than PAST-M.

METHODS

In this double-blind randomized controlled cross-over trial, healthy female (n = 20; 27.3 ± 1.4 y, mean ± SD) habitual dairy consumers, consumed 500 mL of either homogenized bovine UHT-M or PAST-M (1340 compared with 1320 kJ). Gastric content volume (GCV) emptying half-time (T50) was assessed over 3 h by magnetic resonance imaging subjective digestive symptoms, plasma amino acid, lipid and B vitamin concentrations, and gastric myoelectrical activity were measured over 5 h.

RESULTS

Although GCV T50 did not differ (102 ± 7 min compared with 89 ± 8 min, mean ± SEM, UHT-M and PAST-M, respectively; P = 0.051), GCV time to emptying 25% of the volume was 31% longer following UHT-M compared with PAST-M (42 ± 2 compared with 32 ± 4 min, P = 0.004). Although GCV remained larger for a longer duration following UHT-M (treatment × time interaction, P = 0.002), plasma essential amino acid AUC was greater following UHT-M than PAST-M (55,324 ± 3809 compared with 36,598 ± 5673 μmol·min·L-1, P = 0.006). Heat treatment did not impact gastric myoelectrical activity, plasma appetite hormone markers or subjective appetite scores.

CONCLUSIONS

Contrary to expectations, GE was slower with UHT-M, yet, as anticipated, aminoacidemia was greater. The larger GCV following UHT-M suggests that gastric volume may poorly predict circulating nutrient appearance from complex food matrices. Dairy heat treatment may be an effective tool to modify nutrient release by impacting digestion kinetics.

CLINICAL TRIAL REGISTRY

www.anzctr.org.au (ACTRN12620000172909).

Relationships of Intestinal Lactase and the Small Intestinal Microbiome with Symptoms of Lactose Intolerance and Intake in Adults

BACKGROUND

Approximately two-thirds of adults are genetically predisposed to decreased lactase activity after weaning, putting them at risk of lactose intolerance. However, symptoms are a poor marker of lactose maldigestion.

AIMS

We assessed association between self-reported lactose intolerance and intestinal lactase, lactose intake, and the small intestinal microbiome.

METHODS

Patients 18-75 years presenting for upper endoscopy were recruited prospectively. Observational study participants completed a lactose intolerance symptom questionnaire and reported lactose intake. Post-bulbar biopsies were obtained to measure lactase activity and assess the small intestinal mucosal microbiome. We compared intestinal lactase between patients with and without lactose intolerance. We assessed associations between lactose intolerance symptoms and lactase and lactose intake. We examined associations of small bowel microbial composition with self-reported lactose intolerance and symptoms.

RESULTS

Among 34 patients, 23 (68%) reported lactose intolerance. Those with lactose intolerance had higher total symptom scores, more frequent bowel urgency, and more bowel movements after consuming dairy. The proportion of individuals with abnormal lactase activity did not differ by lactose intolerance status. Median lactase levels were correlated with total lactose intolerance symptom scores (p = 0.038) and frequency of bowel urgency (p = 0.012). Daily lactose intake did not differ between groups. In 19 patients, we observed significant associations of small intestinal microbiome beta diversity with stool consistency after consuming dairy (p = 0.03).

CONCLUSIONS

Intestinal lactase is associated with lactose intolerance symptoms and bowel urgency in adults but does not distinguish the clinical phenotype entirely. Studying other contributing factors (microbiota, diet) may further clarify the pathophysiology of lactose intolerance.

Bifidobacterium animalis subsp. lactis Bi-07 supports lactose digestion in vitro and in randomized, placebo- and lactase-controlled clinical trials

BACKGROUND

Probiotics may alleviate lactose maldigestion.

OBJECTIVES

The objective was to select a probiotic with high lactase activity and compare it with lactase and placebo in clinical trials.

METHODS

Bacterial cultures were screened for lactase activity in a model of the upper gastrointestinal (GI) tract. Bifidobacterium animalis subsp. lactis Bi-07 (Bi-07) counts were adjusted in subsequent experiments to correspond to 4500 Food Chemicals Codex (FCC) units of lactase, the amount in the European Food Safety Authority (EFSA)-approved health claim. Two crossover clinical trials, Booster Alpha and Booster Omega, were performed in participants with lactose intolerance, where 2 × 1012 CFUs Bi-07, 4662 FCC lactase, or placebo was consumed simultaneously with a lactose challenge, with 1-wk washouts between challenges. The trial designs were identical except for the source of lactose. Breath hydrogen concentration (BHC) was measured to assess the effect of the investigational products on lactose digestion, for which incremental area under the curve (iAUC) was the primary outcome. Peak BHC, cumulative BHC, and GI symptoms were secondary outcomes.

RESULTS

Bi-07 was superior to placebo in reducing BHC [iAUC, parts per million (ppm) ∙ h] in both trials (Booster Alpha: geometric least square mean ratio: 0.462; 95% CI: 0.249, 0.859; P = 0.016; Booster Omega: 0.227; 95% CI: 0.095, 0.543; P = 0.001). Lactase was superior to placebo in Booster Alpha (0.190; 95% CI: 0.102, 0.365; P < 0.001) but not Booster Omega (0.493; 95% CI: 0.210, 1.156; P = 0.102). Noninferiority of Bi-07 compared with lactase was observed in Booster Omega (0.460; 95% CI: 0.193, 1.096; P = 0.079; CI upper limit < 1.25 noninferiority margin). Odds of abdominal pain (compared with placebo: 0.32, P = 0.036) and flatulence (compared with placebo: 0.25, P = 0.007) were lower with lactase in Booster Alpha. Increased odds of nausea were seen with Bi-07 (compared with placebo: 4.0, P = 0.005) in Booster Omega.

CONCLUSIONS

Bi-07 has high lactase activity, and in 2 clinical trials, it supported lactose digestion in individuals with lactose intolerance.These trials were registered at clinicaltrials.gov as NCT03659747 (Booster Alpha) and NCT03814668 (Booster Omega).

Validation of a modified cow's milk-related symptom score (CoMISS) for screening of lactose intolerance in adults

INTRODUCTION

Lactose intolerance (LI) is the failure to digest foods and beverages containing the lactose present in milk. LI can present by many digestive symptoms.

OBJECTIVE

To validate the modified CoMiSS score for prediction of LI, that was confirmed by a stool acidity test.

PATIENTS AND METHODS

A cross-sectional study, was conducted at Ain Shams University Hospitals/Gastrointestinal Clinics, and included one hundred adult participants during the period from December 2018 to December 2019. Enrolled patients had one or more gastrointestinal symptoms and were subjected to a stool acidity test (fecal PH test) as a reference test and modified CoMiSS as an index test.

RESULTS

The mean age of participants was 35.30 ± 10.714 years old; 55% were females, and their mean body mass index (BMI) was 23.08 ± 2.080 kg/m², with no significant relation between LI and patients` gender or BMI. Out of the studied participants 24% had positive stool PH, LI diagnosed according to modified CoMISS was present among 19% of them. The mean value of modified CoMISS Score was significantly higher in positive cases (12.37) compared to negative LI participants (2.33) as p < .001. Area under ROC Curve was 0.998, at the selected cut-off value 8, the sensitivity was 89.5% and specificity was 100% thus, levels of questionnaire scoring of 8 or higher would indicate presence of lactose intolerance.

CONCLUSION

Modified CoMiSS is a simple, fast, and easy-to-use tool that can predict LI, with a cut-off value of >8, the Area under the ROC Curve was 0.998, sensitivity 89.5%, and specificity was 100%.

Circulatory amino acid responses to milk consumption in dairy and lactose intolerant individuals

Background/objectives

Self-reported digestive intolerance to dairy foods is common. As dairy can be an important source of dietary protein, this study aimed to identify whether milk protein digestion is compromised in individuals with digestive intolerance.

Subjects/methods

Adult women (n = 40) were enroled in this double-blinded, randomised cross-over trial, with digestive symptoms characterised using a lactose challenge and self-reported digestive symptom questionnaire. Participants were classified as either lactose intolerant (LI, n = 10), non-lactose dairy intolerant (NLDI, n = 20) or dairy tolerant (DT, n = 10). In a randomised sequence, participants consumed three different kinds of milk (750 ml); conventional milk (CON), a2 Milk™ (A2M), and lactose-free conventional milk (LF-CON). Circulatory plasma amino acid (AA) concentrations were measured at baseline and every 30 min until 3 h post-ingestion.

Results

In all participants across all milk types, plasma AA concentrations (AUC_0-180) increased after milk ingestion with no significant differences in responses observed between milk types or participants (P > 0.05), with the exception of the suppressed lysine response in the DT group following A2M ingestion, relative to the other two groups and milk types (P < 0.05).

Conclusion

Milk protein digestion, as determined by circulatory AAs, is largely unaffected by dairy- and lactose- intolerances.

Efficacy of i3.1 Probiotic on Improvement of Lactose Intolerance Symptoms: A Randomized, Placebo-controlled Clinical Trial

GOAL

The aim of this study was to assess the efficacy of probiotic i3.1 in improving lactose intolerance symptoms compared with placebo after 8 weeks of treatment.

BACKGROUND

Probiotics are promising strategies to prevent and improve lactose intolerance symptoms, but previous studies have provided conflicting results.

MATERIALS AND METHODS

This randomized, prospective, placebo-controlled study was conducted at the Hospital Juárez de México. We recruited adult patients with lactose intolerance confirmed by a lactose hydrogen breath test (LHBT) ≥20 parts per million (ppm) and a lactose intolerance symptom score ≥6 both upon lactose challenge. We compared the change from baseline in the scores of a validated symptom questionnaire and the LHBT after 8 weeks of probiotic or placebo treatment.

RESULTS

We included 48 patients: 33 receiving the probiotic and 15 receiving placebo (2:1 randomization). Demographic characteristics were homogeneous between groups. The reduction in total symptom score after a lactose challenge was significantly higher in the probiotic group versus the placebo group (-5.11 vs. -1.00; P<0.001). All the subscores significantly decreased from baseline in the probiotic group, except for vomiting, with significant differences between the probiotic and placebo groups for abdominal pain (P=0.045) and flatulence (P=0.004). The area under the curve of the LHBT was significantly reduced from baseline in the probiotic group (P=0.019), but differences between groups were not significant (P=0.621). Adverse events were mild without differences between groups, and no serious adverse event was registered.

CONCLUSION

The i3.1 probiotic was safe and efficacious in reducing lactose intolerance symptoms in patients with lactose intolerance, but did not change the LHBT.

Blinded Oral Challenges with Lactose and Placebo Accurately Diagnose Lactose Intolerance: A Real-Life Study

Lactose intolerance (LI) is characterized by diarrhea, abdominal pain, or bloating occurring after lactose consumption in patients with lactose malabsorption. The National Institute of Health (NIH) proposed a double-blind placebo testing to identify LI individuals correctly. However, until now, no study used this approach in a real-life setting. We aimed to assess double-blind placebo challenge accuracy in diagnosing LI in patients with self-reported symptoms of LI. 148 patients with self-reported LI were consecutively enrolled and blindly underwent hydrogen breath test (HBT) after 25 g lactose or 1 g glucose (placebo) load. One week later, the subjects were challenged with the alternative substrate. Each subject completed a validated questionnaire, including five symptoms (diarrhea, abdominal pain, vomiting, bowel sounds, and bloating) scored on a 10-cm visual analog scale. Home questionnaire (HQ) referred to symptoms associated with the consumption of dairy products at home, while lactose questionnaire (LQ) and placebo questionnaire (PQ) referred to symptoms perceived throughout the 4-h after the administration of the substrates, respectively. After lactose load, HBT was positive in 81 patients (55%), of whom 60 (74%) reported relevant symptoms at LQ (lactose malabsorbers, LM). After placebo challenge, 45 out of 60 with a positive lactose challenge did not complain of symptoms and therefore were diagnosed as lactose intolerant, according to NIH definition. The blinded oral challenges with lactose and placebo accurately diagnose LI and identify patients who will likely benefit from a lactose-free diet.

Effect of lactose intolerance severity on food intake and quality of life in adults with lactose intolerance in Turkey

Purpose

Lactose intolerance is lactose digestive disorder due to lactase enzyme deficiency. This can affect the quality of life by restricting the intake of certain foods. The aim of this study is to show the lactose intolerance to the restriction in food intake and quality of life.

Design/methodology/approach

This study was conducted with adults aged 18–60 years. A survey was used to gather information on the demographic characteristics of the patients and their symptoms related to lactose intolerance. In addition, the Visual Analog Scale was administered to identify common symptoms and the World Health Organization Quality of Life (WHOQOL)-Bref Quality of Life Scale to determine their quality of life.

Findings

The average quality of life subscale scores was 56.25 ± 14.06 for physical, 58.29 ± 11.72 for mental, 63.28 ± 21.35 for social and 62.36 ± 16.37 for environmental. When VAS scores obtained for the common digestive system symptoms in lactose intolerance were compared with Quality of Life scores; it was found that physical life quality scores decreased (r = −0.239, p = 0.030) as the complaints of diarrhea increased and physical and environmental life quality decreased (r = −0.316, p = 0.004/r = −0.277, p = 0.012, respectively) as abdominal pain increased.

Originality/value

People reduce dairy consumption due to digestive system complaints. Therefore, it is important to inform the people about the effects of lactose intolerance because discomfort caused by intolerance can affect nutrient intake and lower the quality of life.

The effect of yogurt fortified with Lactobacillus acidophilus and Bifidobacterium sp. probiotic in patients with lactose intolerance

This study assessed the effect of probiotic yogurt fortified with Lactobacillus acidophilus and Bifidobacterium sp. in patients with lactose intolerance. Fifty-five patients suffering from lactose intolerance were randomly divided into control group of 28 lactose intolerance patients who received nonprobiotic yogurt (100 ml) and experimental group consisted of 27 lactose intolerance patients who received probiotic yogurt fortified (100 ml) with L. acidophilus and Bifidobacterium sp. Each individual received yogurt for one week. Lactose intolerance was confirmed when the patients received 75 g lactose and were positive after 30 min until 3 hr for lactose intolerance symptoms and by hydrogen breath test (HBT). After intervention, the hydrogen level was lower in experimental group in comparison with the control group. Lactose intolerance symptoms in experimental group were much less than the control group. Our findings revealed that probiotic yogurt fortified with L. acidophilus and Bifidobacterium sp. could safely and effectively decrease lactose intolerance symptoms and HBT, so our probiotic can be recommended as a treatment of choice in lactose intolerance patients.

Irritable bowel syndrome and lactose intolerance: the importance of differential diagnosis. A monocentric study

BACKGROUND

Nowadays irritable bowel syndrome (IBS) and lactose intolerance (LI) are two very frequent diseases. IBS is a functional disorder, while LI is caused by the inability to digest lactose. LI is often incorrectly diagnosed as IBS. The aim of our study is to identify LI patients among IBS patients, so as to set up a correct therapy.

METHODS

We enrolled 259 patients with IBS and we compared them to a control group of 108 patients. All patients underwent H<inf>2</inf> Breath-Test (HBT) and two questionnaires regarding the symptoms associated with IBS and LI were administered to the intolerant subjects and one questionnaire to IBS patients with no LI.

RESULTS

At the HBT, 79.9% (N.=207) of patients with IBS were positive, while in the control group were positive 25.0% (N.=27) of subjects (P<0.001). The questionnaires showed, after a month of therapy, a marked improvement in LI symptoms subjects. In addition, there was also a prevalence of more severe symptoms among subjects with IBS and LI than those with IBS and no LI.

CONCLUSIONS

We can affirm that most patients with initial diagnosis of IBS are, instead, lactose intolerant. This diagnosis allows us to undertake an adequate therapy so as to improve symptoms and quality of life. Therefore it is important to include LI in the pathologies with which IBS enters into differential diagnosis.

Comparing Response of Sheep and Cow Milk on Acute Digestive Comfort and Lactose Malabsorption: A Randomized Controlled Trial in Female Dairy Avoiders

Background: Sheep milk (SM) is a possible alternate dairy source for those who experience digestive symptoms with cow milk (CM). While both the milks contain lactose, one of the causes for self-reported intolerance to CM, the composition of SM and CM also differs across proteins and fats, which have been shown to impact digestive processes. Objective: To compare the acute digestive comfort and lactose malabsorption of SM to CM in female dairy avoiders. Method: In a double-blinded, randomized cross over trial, 30 dairy-avoiding females (aged 20-30 years) drank 650 mL of SM or CM (each reconstituted from spray dried powder) following an overnight fast, on two separate occasions at least 1 week apart. Blood samples were collected for glucose and insulin assessment, and single nucleotide polymorphisms of the lactase (LCT) gene (C/T₁₃₉₁₀ and G/A₂₂₀₁₈). Breath H₂ and visual analog scale (VAS) digestive symptom scores were recorded at fasting and regular intervals over 4 h after ingestion. Results: Eighty percentage of study participants were lactase non-persistent (LNP; CC₁₃₉₁₀ and GG₂₂₀₁₈ genotype). Digestive symptoms, including abdominal cramps, distension, rumbling, bloating, belching, diarrhea, flatulence, vomiting, and nausea, were similar in response to SM and CM ingestion (milk × time, P > 0.05). Breath H₂ was greater after CM than SM (72 ± 10 vs. 43 ± 6 ppm at 240 min, P < 0.001), which may be due to greater lactose content in CM (33 vs. 25 g). Accordingly, when corrected for the lactose content breath H₂ did not differ between the two milks. The response remained similar when analyzed in the LNP subset alone (n = 20). Conclusions: Despite a higher energy and nutrient content, SM did not increase adverse digestive symptoms after ingestion, relative to CM, although there was a reduced breath H₂ response, which could be attributed to the lower lactose content in SM. The tolerability of SM should be explored in populations without lactose intolerance for whom underlying trigger for intolerance is unknown.

Carbohydrate-induced gastrointestinal symptoms: development and validation of a test-specific symptom questionnaire for an adult population, the adult Carbohydrate Perception Questionnaire

OBJECTIVES

Carbohydrate intolerances may affect a majority of the worlds-population but there is no validated, test-specific assessment of carbohydrate-induced symptoms during breath tests. We aimed to develop and validate a questionnaire for evaluation and quantification of carbohydrate intolerance.

METHODS

A visual analog scale-questionnaire with five complaints (pain, nausea, bloating, flatulence, and diarrhea) was designed. The time frame of symptoms was 'current' (for baseline symptoms) and 'since filling out the last questionnaire'. Validity was determined in focus-group style interviews and during breath tests in an original (n = 342) and follow-up patient groups (n = 338).

RESULTS

The questionnaire had good face validity, content validity ratio according to Lawshe was 1. Intraclass correlation coefficients (n = 195; 30-min' interval) demonstrated excellent reliability (P < 0.001), Cohen's d (measure of effect size) was small (≤0.19 for each symptom). Convergent and discriminant validity were supported against patient interviews. Questionnaire-derived results highly correlated with a medical interview (P < 0.001; n = 338). Responsiveness to change was verified during breath tests despite small effect sizes (≤0.32). Additional cross-validation and external validation studies (follow-up in-house: n = 182; external: n = 156) demonstrated generalizability and identified relevant numbers of patients in whom there was no co-occurrence of carbohydrate malabsorption and intolerance.

CONCLUSIONS

The adult Carbohydrate Perception Questionnaire is a valid instrument for the assessment of gastrointestinal symptoms after carbohydrate ingestion with excellent psychometric properties. It allows standardized, test-specific diagnosis of carbohydrate intolerance and evaluation of the relation between malabsorption and intolerance. It shall be useful for future studies on treatment of carbohydrate intolerance.

Circulating Branched Chain Amino Acid Concentrations Are Higher in Dairy-Avoiding Females Following an Equal Volume of Sheep Milk Relative to Cow Milk: A Randomized Controlled Trial

Background: Intolerances to bovine dairy are a motivating factor in consumers seeking alternate-or replacement-dairy beverages and foods. Sheep milk (SM) is an alternate dairy source, with greater protein, although similar amino acid composition compared to cow milk (CM). Studies are yet to address the appearance of circulating amino acids following consumption of SM, relative to CM, in humans. Objective: To clinically determine the appearance of branched chain amino acids, and other amino acids, in circulation in response to equal servings of SM and CM, in females who avoid dairy products. Design: In a double-blinded, randomized, cross-over trial, 30 self-described dairy avoiding females (20-40 years) drank 650 mL of SM or CM that were reconstituted from the spray dried powders (30 and 25 g in 180 mL water, respectively) on separate occasions, following an overnight fast. After reconstitution, the energy and protein provided by SM was higher than for CM (2,140 vs. 1,649 kJ; 29.9 vs. 19.4 g protein); content of branched chain amino acids (BCAAs) were 10.5 and 6.5 mg·mL-1, respectively. Blood samples were collected at fasting and at regular intervals over 5 h after milk consumption. Plasma amino acids were measured by HPLC. Results: 80% of subjects self-identified as lactose intolerant, and the majority (47%) "avoided drinking milk" "most of the time". SM resulted in greater plasma appearance of BCAAs at 60 min (641.1 ± 16.3 vs. 563.5 ± 14.4 μmol·L-1; p < 0.001) compared with CM. SM similarly resulted in elevated postprandial concentrations of the amino acids lysine, methionine, and proline, particularly at 240 min (time × milk interactions p = 0.011, 0.017, and p = 0.002, respectively). Postprandial increases in plasma alanine concentrations were sustained to 120 min after CM (time × milk interaction p = 0.001) but not after SM, despite greater quantities provided by SM. Conclusions: SM is a rich source of protein, and relative to CM, provides a greater quantity of BCAAs, with a corresponding elevation of the postprandial circulating BCAA response. SM is therefore a possible dairy alternative of benefit to those who need to increase total protein intake or for individuals with heightened protein requirements. Unique Identifier and Registry: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375324, identifier U1111-1209-7768.

The Effect of Self-Reported Lactose Intolerance and Dairy Consumption on Bone Mineral Density Among American Hip Arthroplasty Patients: A Cross-Sectional Study

The relationship between osteoporosis and lactose intolerance is unclear. This study aims to evaluate the association between self-reported lactose intolerance and symptom severity caused by lactose malabsorption and bone mineral density (BMD). A total of 496 American hip arthroplasty patients took part in this study. Information on BMD and socio-demographic factors were retrospectively extracted from medical records. BMD of the lumbar spine (LS), femoral neck of the operative hip (FNOH), and femoral neck of the non-operative hip (FNH) were measured via dual-energy x-ray absorptiometry scans (DXA). Patients also completed a survey regarding dietary and lifestyle habits from the time of surgery. We found that 9.3% of participants reported lactose intolerance and 33.3%% suffered from either osteopenia or osteoporosis in at least one (location). The population that did not self-identify as lactose intolerant consumed significantly more dairy (p < 0.0001) and animal protein (p = 0.004) than those with intolerance. There was no significant difference in BMD between self-identified lactose intolerant individuals and non-lactose intolerant individuals. In a stepwise multiple regression analysis, body mass index (BMI) and age were the only common predictors of BMD for all locations (p < 0.05). However, yogurt intake was a significant predictor of BMD of FNOH in the multivariate analysis. This study suggests that lactose intolerance is not associated with bone mineral density. We also found that being vegan or vegetarian may increase the risk of low BMD.

Evaluation of breath, plasma, and urinary markers of lactose malabsorption to diagnose lactase non-persistence following lactose or milk ingestion

BACKGROUND

Adult lactase non-persistence (LNP) is due to low lactase expression, resulting in lactose malabsorption (LM). LNP is a genetic trait, but is typically determined by LM markers including breath H2, blood glucose, and urinary galactose after a lactose tolerance test. Known validity of these markers using milk is limited, despite being common practice. Compositional variation, such as β-casein variants, in milk may impact diagnostic efficacy. This study aimed to evaluate the diagnostic accuracy to detect LNP using these commonly measured LM markers after both lactose and milk challenges.

METHODS

Fourty healthy young women were challenged with 50 g lactose then randomized for separate cross-over visits to ingest 750 mL milk (37.5 g lactose) as conventional (both A1 and A2 β-casein) and A1 β-casein-free (a2 Milk™) milk. Blood, breath and urine were collected prior to and up to 3 h following each challenge. The presence of C/T13910 and G/A22018 polymorphisms, determined by restriction fragment length polymorphism, was used as the diagnostic reference for LNP.

RESULTS

Genetic testing identified 14 out of 40 subjects as having LNP (C/C13910 and G/G22018). All three LM markers (breath H2, plasma glucose and urinary galactose/creatinine) discriminated between lactase persistence (LP) and LNP following lactose challenge with an area under the receiver operating characteristic (ROC) curve (AUC) of 1.00, 0.75 and 0.73, respectively. Plasma glucose and urinary galactose/creatinine were unreliable (AUC < 0.70) after milk ingestion. The specificity of breath H2 remained high (100%) when milk was used, but sensitivity was reduced with conventional (92.9%) and a2 Milk™ (78.6%) compared to lactose (sensitivities adjusted for lactose content). The breath H2 optimal cut-off value was lower with a2 Milk™ (13 ppm) than conventional milk (21 ppm). Using existing literature cut-off values the sensitivity and specificity of breath H2 was greater than plasma glucose to detect LNP following lactose challenge whereas values obtained for urinary galactose/creatinine were lower than the existing literature cut-offs.

CONCLUSION

This study showed accurate diagnosis of LNP by breath H2 irrespective of the substrate used, although the diagnostic threshold may vary depending on the lactose substrate or the composition of the milk.

TRIAL REGISTRATION

ACTRN12616001694404 . Registered prospectively on December 9, 2016.

The importance of lactose intolerance in individuals with gastrointestinal symptoms

Lactose intolerance is a condition with an elevated prevalence worldwide, especially in Latin American, Asian, and African countries. The aim of the present narrative review was to highlight the importance of accurately diagnosing lactose intolerance to prevent self-diagnosis that results in the unnecessary elimination of milk and dairy products from the diet and the consequent deprivation of nutrients that could be essential at certain stages of life. The pathophysiologic mechanism of deficient lactose absorption in the intestine can be primary, secondary to other enteropathies, or coexistent with other intestinal diseases with similar symptoms, such as irritable bowel syndrome, bacterial overgrowth syndrome, or celiac disease, causing confusion in relation to diagnosis and treatment. Lactose intolerance consists of a set of symptoms attributed to the consumption of milk and dairy products that are assumed to be due to deficient digestion of that disaccharide. A wide range of tests have been validated to detect deficient digestion that include blood tests, genetic mutation analyses, breath tests, and recently, a urine test, all of which are described in the present article. Nevertheless, there are few validated questionnaires for symptom evaluation and measurement, partly due to the heterogeneity of concepts and the subjectivity of each of the symptoms.

Comparison of the impact of bovine milk β-casein variants on digestive comfort in females self-reporting dairy intolerance: a randomized controlled trial

BACKGROUND

Lactose malabsorption (LM) is a major cause of digestive discomfort from dairy products. Recently, a role for bovine β-casein A1 has been proposed.

OBJECTIVES

We examined whether there are distinct symptoms of digestive discomfort due to either lactose or differing bovine β-casein types.

METHODS

Women (n = 40; age: 25.2 ± 0.5 y) with self-reported varying dairy tolerance underwent a 50-g lactose challenge. Based on postchallenge LM and digestive discomfort, participants were classified as either lactose intolerant (LI; n = 10, self-reported intolerant, diagnosed lactose intolerant), nonlactose dairy intolerant (NLDI; n = 20, self-reported intolerant, diagnosed lactose tolerant), or dairy tolerant (DT; n = 10, self-reported tolerant, diagnosed lactose tolerant). In a double-blinded randomized sequence, participants consumed 750 mL conventional milk (CON; containing A1 and A2 β-casein and lactose), a2 Milk (A2M; exclusively containing A2 β-casein with lactose), or lactose-free conventional milk (LF-CON; containing A1 and A2 β-casein without lactose). Subjective digestive symptoms and breath hydrogen (measuring LM) were recorded regularly over 3 h, and further ad hoc digestive symptoms over 12 h.

RESULTS

LI subjects experienced prolonged digestive discomfort with CON milk. A2M reduced (P < 0.05) some symptoms (nausea: A2M 8 ± 3 mm compared with CON 15 ± 3mm; fecal urgency: A2M 4 ± 1 compared with CON 10 ± 3 mm), and attenuated the rise in breath hydrogen over 3 h, relative to CON milk (A2M 59 ± 23 compared with CON 98 ± 25 ppm at 150 min; P < 0.01). In contrast, NLDI subjects experienced rapid-onset, transient symptoms (abdominal distension, bloating, and flatulence) without increased breath hydrogen, irrespective of milk type.

CONCLUSIONS

In LI individuals, LM and digestive comfort with lactose-containing milks was improved with milk containing exclusively A2 β-casein. Furthermore, self-reported dairy intolerance without LM (NLDI) is characterized by early-onset digestive discomfort following milk ingestion, irrespective of lactose content or β-casein type. This trial was registered at www.anzctr.org.au as ACTRN12616001694404.

Concordance between Lactose Quick Test, hydrogen-methane breath test and genotyping for the diagnosis of lactose malabsorption in children

BACKGROUND

Lactose intolerance is a frequent condition in certain populations. Different methods for diagnosis exist. There is scarce literature regarding Lactose Quick Test (LQT) and concordance with other methods for lactose intolerance diagnosis in children.

METHODS

Prospectively, we included children who underwent gastroduodenoscopy for evaluation of abdominal pain. We obtained a duodenal sample for LQT and blood sample for genetic test to evaluate LCT C>T_-13910 variant. Later, patients underwent breath test with lactose, to evaluate malabsorption. We evaluated the concordance between the three different tests.

KEY RESULTS

We included 46 patients, 56.5% women. Mean age was 13.2 years (range 9-18 years). 66.6% of patients had lactose malabsorption according to breath test; 64.4% were homozygous CC; and 91.3% had hypolactasia (mild or severe) according to LQT. None of the patients with normolactasia had altered breath test. Genetic test had a substantial agreement (k = 0.675) with breath test and fair agreement (k = 0.301) with LQT. LQT had fair agreement (k = 0.348) with breath test.

CONCLUSIONS & INFERENCES

Genetic test had better concordance with breath test than LQT to diagnose lactose malabsorption, however, none of the patients with normal LQT had lactose malabsorption. In patients who undergo gastroduodenoscopy to study abdominal pain, it seems reasonable to perform LQT, and, in those with hypolactasia, to perform breath test.

Lactose malabsorption in systemic sclerosis

BACKGROUND

There are no studies on systemic sclerosis (SSc) assessing the relationship between food intake, especially lactose, and gastrointestinal dysfunction.

AIM

To determine the prevalence of lactose malabsorption, using lactose breath test, in patients with SSc. To evaluate the correlation between lactose malabsorption and gastrointestinal involvement. To predict which SSc patients exhibit lactose malabsorption.

METHODS

Seventy-seven consecutive Caucasian patients with SSc and 20 control subjects underwent lactose breath test. All patients also completed a questionnaire on digestive symptoms, and a global symptom score (GSS) was calculated.

RESULTS

The prevalence of lactose malabsorption was higher in SSc patients than in controls (44.3% vs. 10%; P = 0.004). We observed a marked correlation between the presence of lactose malabsorption and: higher values of GSS (P < 0.0001); severe oesophageal (P = 0.018) and small intestinal (P = 0.04) motor disorders; and joint involvement (P = 0.019). Furthermore, in SSc patients with symptomatic lactose malabsorption, the median value of GSS of digestive symptoms was lower after initiation of lactose-free diet (P < 0.0001).

CONCLUSIONS

Our study underscores the fact that lactose malabsorption often occurs in patients with systemic sclerosis. Furthermore, our findings highlight the fact that lactose breath test is a helpful, noninvasive method, by identifying the group of patients with systemic sclerosis with symptomatic lactose malabsorption that may benefit from a reduction in lactose intake.

Accuracy of a Genetic Test for the Diagnosis of Hypolactasia in Chilean Children: Comparison With the Breath Test

BACKGROUND

Lactase nonpersistence (LNP) in humans is a genetically determined trait. This age-dependent decrease of lactase expression is most frequently caused by single nucleotide polymorphisms in the regulatory region of the lactase (LCT) gene. The homozygous LCT-13,910C/C genotype (rs 4988235) predominates in Caucasian adults with LNP, and is useful for its diagnosis in this population. The accuracy of this genetic test (GT) has not been completely established in children or in a Latin-American population.

OBJECTIVES

The aim of the study was to determine diagnostic accuracy of GT for LNP in Chilean children using the lactose breath test (BT) as a reference, and to compare diagnostic yield in preschool- (<6 years) and in school-age (≥6 years) children.

METHODS

Children referred for BT for diagnosis of lactose malabsorption to the Gastroenterology Laboratory at Clínica Alemana, Santiago, from October 2011 to March 2012 were invited to participate. After informed consent, symptom questionnaires, both historic and post lactose ingestion were completed. H2 and CH4 in expired air and -13,910 C>T single nucleotide polymorphism by polymerase chain reaction, restriction enzyme analysis, and/or Sanger sequencing were determined. GT accuracy was calculated compared to BT as reference method. Diagnostic yield of GT in preschool- and school-age children was compared.

RESULTS

Lactose malabsorption was detected by BT in 42 of 60 children (70%). Genotype -13,910C/C was identified in 41 of 60 patients (68%). GT showed 80% sensitivity, 63% specificity, and 74% accuracy for LNP in the preschool population. In school-age children values were higher, 85%, 80%, and 84%, respectively.

CONCLUSIONS

GT results were significantly concordant with BT results for hypolactasia detection in Chilean children, particularly in those of age 6 years and older.

The effects of the DDS-1 strain of lactobacillus on symptomatic relief for lactose intolerance - a randomized, double-blind, placebo-controlled, crossover clinical trial

BACKGROUND

Lactose intolerance is a form of lactose maldigestion where individuals experience symptoms such as diarrhea, abdominal cramping, flatulence, vomiting and bowel sounds following lactose consumption. Lactobacillus acidophilus is a species of bacteria known for its sugar fermenting properties. Preclinical studies have found that Lactobacillus acidophilus supplementation may assist in breaking down lactose; however, no human clinical trials exist evaluating its efficacy in alleviating symptoms related to lactose intolerance.

OBJECTIVE

The aim of this randomized, double-blind, placebo-controlled, crossover study was to evaluate the effect of a proprietary strain of Lactobacillus acidophilus on relieving discomfort related to lactose intolerance.

METHODS

The study enrolled healthy volunteers between 18 and 75 years of age who complained of lactose intolerance. Screening visits included a lactose challenge visit to confirm eligibility based on a score of 10 or higher on subjective assessment of the following symptoms after lactose challenge: diarrhea, abdominal cramping, vomiting, audible bowel sounds, flatulence, and overall symptoms. Qualified subjects participated in a 2-arm crossover design, with each arm consisting of 4 weeks of intervention of either active or placebo product, with a 2-week washout period during crossover. The study product consisted of the DDS-1 strain of Lactobacillus acidophilus (Nebraska Cultures, Walnut Creek, California). The placebo was formulated from maltodextrin. Study participants were instructed to take the product once daily for 4 weeks. Data collected included subjective symptom scores related to lactose intolerance.

RESULTS

Longitudinal comparison between the DDS-1 group and placebo group demonstrated statistically significant reductions in abdominal symptom scores during the 6-h Lactose Challenge at week 4 for diarrhea (p = 0.033), abdominal cramping (p = 0.012), vomiting (p = 0.0002), and overall symptom score (p = 0.037). No adverse events were reported.

CONCLUSIONS

The present study has found that this unique DDS-1 strain of Lactobacillus acidophilus, manufactured by Nebraska Cultures, is safe to consume and improves abdominal symptom scores compared to placebo with respect to diarrhea, cramping, and vomiting during an acute lactose challenge.

Perception of lactose intolerance impairs health-related quality of life

BACKGROUND/OBJECTIVES

Chronic conditions impair perception of well-being. Malabsorption of lactose is the most frequent form of malabsorption and manifests as lactose intolerance. There is a lack of information regarding their impact on self-perception of health. The objective of this study is to determine the subjective impact of self-reported lactose intolerance or objective lactose malabsorption on patient health by using a patient-reported outcome to measure health-related quality of life (HRQOL) and modification of lactose-containing food diet.

SUBJECTS/METHODS

A 3-year prospective, cross-sectional study was performed in patients referred for a lactose hydrogen breath test. Patients were asked about their subjective opinion relative to their lactose tolerance and completed a validated, specific questionnaire to determine symptoms of intolerance during habitual consumption of dairy. A 50-g lactose breath test was then performed. Patients were grouped as absorbers vs malabsorbers and tolerant vs intolerants.

RESULTS

A total of 580 patients were included (median age 30 years, 419 female). Overall, 324 patients (56%) considered themselves lactose intolerant and that perception was associated with avoidance of dairy consumption (55% vs only 9% of self-defined tolerants). Self-perception of intolerance was associated with lower HRQOL scores (median, 60 vs 70, P<0.01). In contrast, lactose objective malabsorption was not clearly associated with dairy avoidance (41% of malabsorbers avoided dairy vs 31% of absorbers). However, HRQOL scores were also significantly lower in malabsorbers than in absorbers (60 vs 70 respectively, P<0.001).

CONCLUSIONS

Subjective perception of lactose intolerance affects the decision to avoid dairy even more than objective malabsorption. However, both self-perception of lactose intolerance and objective lactose malabsorption are associated with poorer perceived quality of life.

Primary hypolactasia diagnosis: Comparison between the gaxilose test, shortened lactose tolerance test, and clinical parameters corresponding to the C/T-13910 polymorphism

BACKGROUND & AIMS

There is no consensus on the most accurate method to diagnose primary hypolactasia. We aimed to compare the diagnostic accuracy of the new gaxilose test with 2 traditional tests (lactose tolerance test and clinical criteria) for the diagnosis of primary hypolactasia using the C/T-13910 polymorphism as a reference standard.

METHODS

Patients with a clinical suspicion of lactose intolerance were subjected to gaxilose tests, shortened lactose tolerance tests, and symptom questionnaires before and after overload with 50 g lactose and after a lactose-free diet. The diagnostic accuracy and degree of agreement and correlation were assessed using a genetic test (C/T-13910 polymorphism) as a reference standard and their respective 95% confidence intervals.

RESULTS

Thirty consecutive patients (70% women) participated in the study. The genetic test confirmed the C/T-13910 polymorphism in 11 patients (36.8%). The presence of diarrhoea and the symptom score after lactose overload, along with the tolerance test, were the variables with the highest degree of agreement (κ > 0.60). Area under the ROC curve was >0.82 (p < 0.05), with sensitivity and specificity values of >0.80. However, the gaxilose test obtained lower values: κ, 0.47; area under curve, 0.75 (0.57-0.94); sensitivity, 0.82 (0.55-1); and specificity, 0.68 (0.45-0.92). The multivariate analysis showed an association between the post-overload symptom questionnaire and the results of the genetic test (odds ratio: 1.17; 1.04-1.31; p < 0.01).

CONCLUSIONS

The presence of diarrhoea and the symptom score after overload with 50 g lactose showed a higher degree of agreement and diagnostic accuracy for primary hypolactasia than the gaxilose test when the genetic test is used as a reference standard.

Prevalence of lactose intolerance in Chile: a double-blind placebo study

BACKGROUND AND STUDY AIMS

Lactase non-persistence (LNP), or primary hypolactasia, is a genetic condition that mediates lactose malabsorption and can cause lactose intolerance. Here we report the prevalence of lactose intolerance in a double-blind placebo study.

METHODS

The LCT C>T-13910 variant was genotyped by RT-PCR in 121 volunteers and lactose malabsorption was assessed using the hydrogen breath test (HBT) after consuming 25 g of lactose. Lactose intolerance was assessed by scoring symptoms (SS) using a standardized questionnaire following challenge with a lactose solution or saccharose placebo.

RESULTS

The LNP genotype was observed in 57% of the volunteers, among whom 87% were HBT⁺. In the HBT⁺ group the median SS was 9 and in the HBT⁻ group the median SS was 3 (p < 0.001). No difference was observed in the SS when both groups were challenged with the placebo. The most common symptoms included audible bowel sounds, abdominal pain and meteorism. In the ROC curve analysis, an SS ≥ 6 demonstrated 72% sensitivity and 81% specificity for predicting a positive HBT. To estimate prevalence, lactose intolerance was defined as the presence of an SS ≥ 6 points after subtracting the placebo effect and 34% of the study population met this definition.

CONCLUSIONS

The LNP genotype was present in more than half of subjects evaluated and the observed prevalence of lactose intolerance was 34%.

Perception of lactose intolerance in irritable bowel syndrome patients

INTRODUCTION

The importance of lactose malabsorption in irritable bowel syndrome (IBS) is not well defined and these patients often complain of lactose intolerance. To objectively measure lactose malabsorption, a hydrogen breath test (HBT) can be performed, but a discrepancy emerges between the results of the HBT and the symptomatic response during the HBT.

AIMS

To determine in a group of IBS patients whether self-perceived lactose intolerance and the symptomatic response to lactose HBT were conditioned by other factors besides the presence of lactose malabsorption.

MATERIALS AND METHODS

Oral challenge to lactose (50 g) was tested in 51 IBS patients to assess HBT malabsorption and the symptomatic response to lactose intolerance was scored on a validated questionnaire. Allergological screening for common inhalants and food allergens (including cow's milk) was performed. The presence of psychological factors (e.g. anxiety, depression, fatigue) was evaluated using validated questionnaires.

RESULTS

A total of 21 out of 51 patients (41.1%) were self-perceived to be lactose intolerant, 24/51 (47%) had a positive HBT, and 14/51 (27.4%) presented with symptoms of lactose intolerance during HBT. The serological screening for inhalant and food allergens was positive in 6/21 (28.6%) and 4/21 (19%) of patients who self-perceived lactose intolerance and in 5/14 (37.5%) and 3/14 (21.4%) in intolerant patients symptomatic during HBT. Only 1/51 (1.9%) presented evidence of IgE-mediated hypersensitivity to cow's milk. Patients who experienced symptoms of lactose intolerance during HBT presented more severe IBS symptoms [326 (296-398) vs. 215 (126-295) P=0.05] and a higher score of anxiety, depression, and fatigue. Factors influencing the symptoms of lactose intolerance during HBT resulted in an increase in hydrogen produced and in the severity of IBS.

CONCLUSION

In a cohort of 51 IBS patients, the symptoms of lactose intolerance during HBT were influenced by the capacity to absorb lactose and the severity of IBS. Other factors, such as the psychological status or an adverse reaction to milk, merit consideration as potential cofactors involved in lactose perception and tolerance.

Enteric-coated capsule containing β-galactosidase-loaded polylactic acid nanocapsules: enzyme stability and milk lactose hydrolysis under simulated gastrointestinal conditions

In order to protect peroral β-galactosidase from being degraded and hydrolyse milk lactose efficiently in the environments of gastrointestinal tract, a double-capsule delivery system composed of enteric-coated capsule and polylactic acid (PLA) nanocapsules (NCs) was developed for encapsulation of β-galactosidase. β-galactosidase-loaded PLA NCs in the size range of 100–200 nm were prepared by a modified w1/o/w2technique. During the encapsulation process, dichloromethane/ethyl acetate (1 : 1, v/v) as the solvent composition, high-pressure homogenisation (150 bar, 3 min) as the second emulsification method and polyvinyl alcohol or Poloxamer 188 as a stabiliser in the inner phase could efficiently improve the activity retention of β-galactosidase (>90%). Subsequently, the prepared NCs were freeze-dried and filled in a hydroxypropyl methylcellulose phthalate (HP55)-coated capsule. In vitro results revealed that the HP55-coated capsule remained intact in the simulated gastric fluid and efficiently protected the nested β-galactosidase from acidic denaturation. Under the simulated intestinal condition, the enteric coating dissolved rapidly and released the β-galactosidase-loaded PLA NCs, which exhibited greater stability against enzymatic degradation and higher hydrolysis ratio (∼100%) towards milk lactose than the free β-galactosidase. These results suggest that this double-capsule delivery system represents promising candidate for efficient lactose hydrolysis in the gastrointestinal tract.

Poly(lactic acid) nanoparticles coated with combined WGA and water-soluble chitosan for mucosal delivery of β-galactosidase

A combinatorial design, physical adsorption of water-soluble chitosan (WSC) to particle surface and covalent conjugation of wheat germ agglutinin (WGA) to WSC, was applied to surface modification of poly(lactic acid) nanoparticles (NPs) for targeted delivery of β-galactosidase to the intestinal mucosa. All the surface-engineered NPs in the size range of 500-600 nm were prepared by a w/o/w solvent diffusion/evaporation technique. β-Galactosidase encapsulated in these NPs was well protected from external proteolysis and exerted high hydrolytic activity on the permeable lactose. The presence of WSC coating, whether alone or with WGA, highly improved the suspension stability of NPs and tailored the particle surface positively charged. In comparison to NPs modified with WGA or WSC alone, the synergistic action of WGA and WSC greatly enhanced the NP-mucin interactions in vitro. The highest amount of NPs was found in the small intestine at 24 h after oral administration in rats. Notably, calculated half-life of WGA-WSC-NPs in the small intestine was 6.72 h, resulting in 2.1- and 4.3-fold increase when compared to WGA-polyvinylalcohol (PVA)-NPs and WSC-NPs, much longer than that of control PVA-NPs (6.9-fold). These results suggest that NPs with the combined WGA and WSC coating represent promising candidates for efficient mucosal drug delivery as well as biomimetic treatment of lactose intolerance.

Development of an online library of patient-reported outcome measures in gastroenterology: the GI-PRO database

OBJECTIVES

Because gastrointestinal (GI) illnesses can cause physical, emotional, and social distress, patient-reported outcomes (PROs) are used to guide clinical decision making, conduct research, and seek drug approval. It is important to develop a mechanism for identifying, categorizing, and evaluating the over 100 GI PROs that exist. Here we describe a new, National Institutes of Health (NIH)-supported, online PRO clearinghouse-the GI-PRO database.

METHODS

Using a protocol developed by the NIH Patient-Reported Outcome Measurement Information System (PROMIS(®)), we performed a systematic review to identify English-language GI PROs. We abstracted PRO items and developed an online searchable item database. We categorized symptoms into content "bins" to evaluate a framework for GI symptom reporting. Finally, we assigned a score for the methodological quality of each PRO represented in the published literature (0-20 range; higher indicates better).

RESULTS

We reviewed 15,697 titles (κ>0.6 for title and abstract selection), from which we identified 126 PROs. Review of the PROs revealed eight GI symptom "bins": (i) abdominal pain, (ii) bloat/gas, (iii) diarrhea, (iv) constipation, (v) bowel incontinence/soilage, (vi) heartburn/reflux, (vii) swallowing, and (viii) nausea/vomiting. In addition to these symptoms, the PROs covered four psychosocial domains: (i) behaviors, (ii) cognitions, (iii) emotions, and (iv) psychosocial impact. The quality scores were generally low (mean 8.88 ± 4.19; 0 (min)-20 (max). In addition, 51% did not include patient input in developing the PRO, and 41% provided no information on score interpretation.

CONCLUSIONS

GI PROs cover a wide range of biopsychosocial symptoms. Although plentiful, GI PROs are limited by low methodological quality. Our online PRO library (www.researchcore.org/gipro/) can help in selecting PROs for clinical and research purposes.

Bloating and distention in irritable bowel syndrome: the role of gas production and visceral sensation after lactose ingestion in a population with lactase deficiency

OBJECTIVES

Bloating and distention are often attributed to dietary factors by patients with irritable bowel syndrome (IBS). This study examined the effects of gas production and visceral hypersensitivity on digestive symptoms after lactose ingestion in a population with lactase deficiency.

METHODS

IBS patients (n=277) and healthy controls (HCs, n=64) underwent a 20-g lactose hydrogen breath test (LHBT) with evaluation of hydrogen gas production and lactose intolerance (LI) symptoms. Abdominal distention (199 IBS, 40 HCs) was measured during LHBT. Rectal sensitivity (74 IBS, 64 HCs) was assessed by barostat studies.

RESULTS

Hydrogen production and distention were similar in IBS patients and HCs during LHBT; however, LI was more frequent in IBS (53.8 vs. 28.1%, P<0.001), especially bloating (39.0% vs. 14.1%, P<0.001) and borborygmi (39.0 vs. 21.9%, P=0.010). Only 59.0% of patients with bloating had distention. No correlation was observed between girth increment and bloating (P=0.585). IBS patients had lower rectal sensory thresholds (P=0.001). Multivariate analysis indicated that hydrogen production increased bloating (odds ratio (OR) 2.19, 95% confidence interval (CI) 1.09-4.39, P=0.028) and borborygmi (OR 12.37, 95% CI 3.34-45.83, P<0.001) but not distention (P=0.673). Visceral hypersensitivity was associated with bloating (OR 6.61, 95% CI 1.75-25.00, P=0.005) and total symptom score (OR 3.78, 95% CI 1.30-10.99, P=0.014).

CONCLUSIONS

Gas production and visceral hypersensitivity both contribute to digestive symptoms, especially bloating and borborygmi, in IBS patients after lactose ingestion. Objective abdominal distention is not correlated with subjective bloating.

Agreement between indirect calorimetry and traditional tests of lactose malabsorption

BACKGROUND

Lactose malabsorption occurs frequently and the variable consequent intolerance may seriously impair quality of life. No reliable and convenient test method is in routine clinical practice. A recent animal study showed that the respiratory quotient changed significantly after ingestion of sucrose and lactose in naturally lactase-deficient rats.

AIMS

This exploratory study evaluated the relevance of monitoring the respiratory quotient after lactose ingestion to detect malabsorption.

METHODS

Healthy volunteers were identified and classified lactose absorbers and malabsorbers by a lactose tolerance test (25 g). After an overnight fast, a second lactose challenge was performed to monitor hydrogen excretion and respiratory quotient kinetics over 4h. Participants also completed questionnaires to score and localise their gastrointestinal symptoms.

RESULTS

20 subjects were enrolled (10 per group, 60% males, mean age 34 ± 4 years). Respiratory quotient kinetics were different between absorbers and malabsorbers during the first 100 min after lactose ingestion (p<0.01) and during the initial 30-50 min period. Respiratory quotient was significantly, positively correlated to peak glycaemia (R=0.74) and negatively correlated to hydrogen excretion (R=-0.51) and symptoms score (R=-0.46).

CONCLUSIONS

Indirect calorimetry could improve the reliability of lactose malabsorption diagnosis. Studies on larger populations are needed to confirm the validity of this test and propose a simplified measurement.

Is the subjective perception of lactose intolerance influenced by the psychological profile?

BACKGROUND

Symptoms of lactose intolerance are often attributed to lactose malabsorption but, as this relationship has not been demonstrated when a small dose of lactose similar to that contained in one cup of milk is ingested by intolerant patients, psychological factors may play a role in altered symptom perception.

AIM

To assess the hypothesis that the psychological profile influences the symptoms of lactose intolerance.

METHODS

One hundred and two consecutive patients underwent a 15 g lactose hydrogen breath test to assess lactose malabsorption. The patients recorded the presence and severity of symptoms of lactose intolerance during the breath test using visual analogue scales. The psychological profile was assessed using a psychological symptom checklist, and health-related quality of life by means of the short-form health survey.

RESULTS

Lactose malabsorption and intolerance were diagnosed in, respectively, 18% and 29% of the patients. The two conditions were not associated, and the severity of intolerance was even less in the patients with malabsorption. Multivariate logistic analysis showed that a high somatisation t-score was significantly associated with lactose intolerance (odds ratio 4.184; 1.704-10.309); the effects of the other psychological variables and of lactose malabsorption were not statistically significant. Health-related quality of life was significantly reduced in the patients with somatisation, but not in those with lactose malabsorption.

CONCLUSIONS

The symptoms of lactose intolerance during hydrogen breath testing at a low physiological lactose load, are unrelated to lactose malabsorption, but may reveal a tendency towards somatisation that could impair the quality of life.

Lactose intolerance: diagnosis, genetic, and clinical factors

Most people are born with the ability to digest lactose, the major carbohydrate in milk and the main source of nutrition until weaning. Approximately 75% of the world’s population loses this ability at some point, while others can digest lactose into adulthood. This review discusses the lactase-persistence alleles that have arisen in different populations around the world, diagnosis of lactose intolerance, and its symptomatology and management.

Lactase non-persistent genotype influences milk consumption and gastrointestinal symptoms in Northern Russians

BACKGROUND

Milk is an important source of nutrients. The consumption of milk, however, may cause abdominal complaints in lactose intolerant individuals. The frequency of -13910C/C genotype is known to be high among Northern Russians, exceeding the prevalence in northern Europe. In our study we tested two hypotheses: 1) subjects with lactase non-persistent genotype (-13910C/C) have more gastrointestinal (GI) symptoms associated with milk 2) subjects with lactase non-persistence avoid using milk.

METHODS

In total, 518 students aged 17 to 26 years were randomly selected from different departments in the Northern State Medical University (NSMU) for genotyping the lactase activity-defining -13910C/T variant. All subjects filled in a questionnaire covering their personal data, self-reported GI symptoms and milk consumption habits.

RESULTS

Northern Russians consume very small amounts of milk daily. Among carriers of the lactase non-persistent (LNP) genotype there were 10 percentage units of milk-consumers fewer than among lactase-persistent (LP) subjects (p = 0.03). Complaints of GI disorders caused by milk were different between the genotypes (p = 0.02). Among all types of food analyzed only milk was associated with increased GI symptoms among subjects with the LNP genotype (OR = 1.95, CI 1.03-3.69)

CONCLUSIONS

Subjects with -13910C/C have more GI symptoms from milk. Subjects with lactase non-persistent genotype avoid using milk. In the case of increasing milk consumption symptoms may increase the need for medical consultation. It is thus important either for people themselves or for health care staff to be aware of lactase persistence/non-persistence.

Lactose malabsorption and intolerance: a systematic review on the diagnostic value of gastrointestinal symptoms and self-reported milk intolerance

BACKGROUND

When lactose malabsorption gives rise to symptoms, the result is called 'lactose intolerance'. Although lactose intolerance is often bothersome for patients, once recognized it may be managed by simple dietary adjustments. However, diagnosing lactose intolerance is not straightforward, especially in primary care.

AIM

To summarize available evidence on the diagnostic performance of gastrointestinal symptoms and self-reported milk (lactose) intolerance in primary care, and the relationship between lactose malabsorption and intolerance.

DATA SOURCES

PubMed, EMBASE and reference screening.

STUDY SELECTION

Studies were selected if the design was a primary diagnostic study; the patients were adults consulting because of non-acute abdominal symptoms; the diagnostic test included gastrointestinal symptoms and/or self-reported milk intolerance. A total of 26 primary diagnostic studies were included in the review.

DATA EXTRACTION

Quality assessment and data extraction were performed by two reviewers independently. They adhered to the most recent guidelines for conducting a diagnostic review as described in the Cochrane Diagnostic Reviewers' Handbook.

RESULTS

The diagnostic performance of diarrhea, abdominal pain, bloating, flatulence and self-reported milk intolerance was highly variable. A non-Caucasian ethnic origin was associated with the presence of lactose malabsorption. Both lactose malabsorbers and lactose absorbers reported symptoms during the lactose hydrogen breath test.

CONCLUSION

Our review shows that high-quality studies on the diagnosis of lactose malabsorption and intolerance in primary care are urgently needed. An important prerequisite would be to clearly define the concept of lactose intolerance, as well as how it should be assessed.

Subjective perception of lactose intolerance does not always indicate lactose malabsorption

BACKGROUND & AIMS

Symptomatic lactose intolerance is common; however, abdominal symptoms that patients experience after ingestion of lactose-containing foods can have causes beyond lactose malabsorption. We aimed to determine whether symptoms that patients usually attribute to lactose intolerance are comparable to symptoms provoked by a controlled lactose challenge and whether these symptoms are related to lactose absorption capacity.

METHODS

We performed an observational, prospective, transverse study of 353 patients referred for a lactose hydrogen breath test (HBT). Patients completed a validated questionnaire about symptoms associated with consumption of dairy products at home (home symptoms). After a 50-g lactose breath test, they completed the same questionnaire again (lactose challenge symptoms). Patients were assigned to groups of absorbers or malabsorbers according to HBT results and tolerants or intolerants according to the results of the questionnaire.

RESULTS

The total symptom score was significantly higher for home symptoms than for the lactose challenge (16 vs 8, P < .01). Symptoms perceived at home were reported to be more intense than those that followed the lactose challenge for lactose absorbers compared with malabsorbers (16 vs 4, P < .01) and lactose tolerants compared with intolerants (12 vs 2, P < .05). Overperception of lactose intolerance at home was similar in men and women.

CONCLUSIONS

Daily life symptoms that patients associate with lactose intolerance are often unrelated to lactose malabsorption. Even among true lactose malabsorbers, symptom recall tends to be amplified by the patient. Thus, conventional anamnesis is a highly unreliable tool to establish symptomatic lactose malabsorption.

A comparison of diagnostic tests for lactose malabsorption--which one is the best?

Background

Perceived milk intolerance is a common complaint, and tests for lactose malabsorption (LM) are unreliable. This study assesses the agreement between diagnostic tests for LM and describes the diagnostic properties of the tests.

Methods

Patients above 18 years of age with suspected LM were included. After oral intake of 25 g lactose, a combined test with measurement of serum glucose (s-glucose) and hydrogen (H2) and methane (CH4) in expired air was performed and symptoms were recorded. In patients with discrepancies between the results, the combined test was repeated and a gene test for lactose non-persistence was added. The diagnosis of LM was based on an evaluation of all tests. The following tests were compared: Increase in H2, CH4, H2+CH4 and H2+CH4x2 in expired air, increase in s-glucose, and symptoms. The agreement was calculated and the diagnostic properties described.

Results

Sixty patients were included, seven (12%) had LM. The agreement (kappa-values) between the methods varied from 0.25 to 0.91. The best test was the lactose breath test with measurement of the increase in H2 + CH4x2 in expired air. With a cut-off level < 18 ppm, the area under the ROC-curve was 0.967 and sensitivity was 100%. This shows that measurement of CH4 in addition to H2 improves the diagnostic properties of the breath test.

Conclusion

The agreement between commonly used methods for the diagnosis of LM was unsatisfactory. A lactose breath test with measurement of H2 + CH4x2 in expired air had the best diagnostic properties.